From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98A10C433FE for ; Wed, 24 Nov 2021 12:52:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344893AbhKXMzV (ORCPT ); Wed, 24 Nov 2021 07:55:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:56074 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344485AbhKXMuJ (ORCPT ); Wed, 24 Nov 2021 07:50:09 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1BD5B610E9; Wed, 24 Nov 2021 12:29:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637756949; bh=7DLh4txpxMQIEJZ6/SIU7QDmWoljzqIfb6aw6fP9rfk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e44O6E2soR/sYmQuMaxZX64MfEgZfSxFV8SkLPb8+jDFkBKOLRi/ceIu4NXmI7wHK 0dakQz5AJmRMxVVHpUGGnycVhA3EBxPpwAn7L+tgeCfNndRcR7ZSfqYOxNyK3HQ2Xy 9PzvMTcqxyT6va6mxuNuKS3H2/0y5Tzu2po5lpng= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Subject: [PATCH 4.14 250/251] usb: max-3421: Use driver data instead of maintaining a list of bound devices Date: Wed, 24 Nov 2021 12:58:12 +0100 Message-Id: <20211124115719.021343375@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115710.214900256@linuxfoundation.org> References: <20211124115710.214900256@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Uwe Kleine-König commit fc153aba3ef371d0d76eb88230ed4e0dee5b38f2 upstream. Instead of maintaining a single-linked list of devices that must be searched linearly in .remove() just use spi_set_drvdata() to remember the link between the spi device and the driver struct. Then the global list and the next member can be dropped. This simplifies the driver, reduces the memory footprint and the time to search the list. Also it makes obvious that there is always a corresponding driver struct for a given device in .remove(), so the error path for !max3421_hcd can be dropped, too. As a side effect this fixes a data inconsistency when .probe() races with itself for a second max3421 device in manipulating max3421_hcd_list. A similar race is fixed in .remove(), too. Fixes: 2d53139f3162 ("Add support for using a MAX3421E chip as a host driver.") Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211018204028.2914597-1-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/max3421-hcd.c | 25 +++++-------------------- 1 file changed, 5 insertions(+), 20 deletions(-) --- a/drivers/usb/host/max3421-hcd.c +++ b/drivers/usb/host/max3421-hcd.c @@ -121,8 +121,6 @@ struct max3421_hcd { struct task_struct *spi_thread; - struct max3421_hcd *next; - enum max3421_rh_state rh_state; /* lower 16 bits contain port status, upper 16 bits the change mask: */ u32 port_status; @@ -170,8 +168,6 @@ struct max3421_ep { u8 retransmit; /* packet needs retransmission */ }; -static struct max3421_hcd *max3421_hcd_list; - #define MAX3421_FIFO_SIZE 64 #define MAX3421_SPI_DIR_RD 0 /* read register from MAX3421 */ @@ -1835,9 +1831,8 @@ max3421_probe(struct spi_device *spi) } set_bit(HCD_FLAG_POLL_RH, &hcd->flags); max3421_hcd = hcd_to_max3421(hcd); - max3421_hcd->next = max3421_hcd_list; - max3421_hcd_list = max3421_hcd; INIT_LIST_HEAD(&max3421_hcd->ep_list); + spi_set_drvdata(spi, max3421_hcd); max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL); if (!max3421_hcd->tx) @@ -1882,28 +1877,18 @@ error: static int max3421_remove(struct spi_device *spi) { - struct max3421_hcd *max3421_hcd = NULL, **prev; - struct usb_hcd *hcd = NULL; + struct max3421_hcd *max3421_hcd; + struct usb_hcd *hcd; unsigned long flags; - for (prev = &max3421_hcd_list; *prev; prev = &(*prev)->next) { - max3421_hcd = *prev; - hcd = max3421_to_hcd(max3421_hcd); - if (hcd->self.controller == &spi->dev) - break; - } - if (!max3421_hcd) { - dev_err(&spi->dev, "no MAX3421 HCD found for SPI device %p\n", - spi); - return -ENODEV; - } + max3421_hcd = spi_get_drvdata(spi); + hcd = max3421_to_hcd(max3421_hcd); usb_remove_hcd(hcd); spin_lock_irqsave(&max3421_hcd->lock, flags); kthread_stop(max3421_hcd->spi_thread); - *prev = max3421_hcd->next; spin_unlock_irqrestore(&max3421_hcd->lock, flags);